1. Field of the Invention
The present invention relates to a shut-off (open/close) valve for shutting off (opening and closing) openings formed to a vacuum chamber and also relates to a method of shutting off the openings by using such shut-off valve.
2. Related Art
A shut-off valve provided for opening or closing a vacuum chamber of a vacuum device such as semiconductor manufacturing device has been variously studied and developed, and the inventor of the subject application had already provided such shut-off valve as disclosed, for example, in Japanese Patent Laid-Open (KOKAI) Publication No. HEI 11-351448.
The shut-off valve disclosed in this publication is arranged horizontally between lateral vacuum chambers. This shut-off valve comprises a valve seat having lateral communication openings, a valve body which is arranged to be rotatable and movable in an axial direction of the valve seat and a driving mechanism for rotating and moving the valve body in the axial direction. An O-ring is further provided to the outer peripheral surface of the valve body so as to surround the communication openings of the valve seat to thereby surely seal the openings.
In the above aspect, it may be said that the shut-off valve of the structure mentioned above is superior in the point of ensuring the vacuum condition at high performance in the vacuum chamber. However, with such shut-off valve, the O-ring is rubbed against the inner surface of a casing of the vacuum device every time the valve body rotates, which may cause, so-called, particles, thus being inconvenient.